Onyx is a kind of metamorphic rock resulting from local metamorphism of calcium- and magnesium-containing calcareous stones. It is a layered stone with various colors, crystalline, and semi-transparent. In fact, Onyx belongs to Marble Group is in scientific terms. Its main applications is in the interior façade and sculpture. So far, its largest reserves have been reported in the provinces of East Azerbaijan, Khorasan, Kerman and Kurdistan. The countries of Italy, Iran, Turkey and Pakistan have the largest reserves of Onyx stone in the world, which are of a great diversity.
The resistance of this rock against weathering, gases and acid rain is low. Therefore, this stone is used in the interior facade of buildings.
- Low porosity
- Prettiness and colorful variety, especially in Iran
- Abrasiveness and having the perfect luster (in stone finishing stage)
- Suitable for work in interior facades and sculpture and artwork
- Onyx has a commonality with Travertine stone. Today, the use of Book Match designs on the floor of the lobby and important parts of the building with Onyx and travertine is very common and, of course, it is beautiful and eye-catching. The impressions created on travertine rocks can show a very artistic painting with a variety of designs, , if they preserve their orientation during cutting and subjected to a combination of processing.
- Onyx resistance against moisture, air pollution and sulfur gases is low, therefore, it is not suitable for exterior facades of buildings in polluted cities.